Blue Exorcist: Ignited By The Blue Flames
by Espeon804
Summary: Satan had been defeated, and it's back to cram school for the students of the True Cross Academy. Everything seemed of ease, until suddenly the school was attacked by a demon crying out for vengeance... one never faced before. The demons were retaliating, and the students put what they learned in action. But when the situation turns bleak, they didn't expect the teacher to forget
1. Part 1: Hold Composure

**A/N:** **Espeon804 here with another great fanfic!**

…

 **What?**

 **You didn't expect this?**

 **Well… it's true, I'm a huge fan of Pokémon and the Dragon Ball series but… Blue Exorcist is a good show too.**

 **So, I've been going through Fanfiction and Wattpad… not either website has (maybe rarely, but I never saw one) a fanfic like the one I'm about to show you. I wouldn't be doing this if it was common.**

 **Well, anyway, this is my FIRST Blue Exorcist fanfic, so it may not be as great as my DBZ ones…**

 **Hey. I get better.**

 **So… LISTEN!**

 **I watched the whole season through the English Dub. Occasionally, I check it out in the original Japanese to compare the voices. (English doesn't put in as much effort with the acting it seems. :P)**

 **So basically, this is based from the anime. That should clarify a few things.**

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Key:

"Talking"

' _Thinking'_

" **Telepathy"**

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 **DISCLAIMER:** **I DO NOT OWN Blue Exorcist (Ao no Exorcist)**

 **Kazue Kato owns it all!**

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 **\- Part 1: Hold composure-**

"Alright class, that should be… just about it." A book on a desk is shut lightly, and the hand rests on the surface. The other hand rises to the bridge of the owner's nose to push the glasses back in place to readjust them. The pair of blue eyes blink. "You may be dismissed."

Though he says this, the class doesn't budge. Pairs of eyes blink at him, a few would shift and turn to the books as they begun to gather the stacks in their arms.

The teacher frowns somewhat. This is the third time they were rather hesitant to leave. He steps from behind his desk. "I would appreciate it if one of you would explain why you're not so urgent to leave the class as usual?" His eyes shift to the shy student in the class. "Shiemi?"

The girl blinks as if she was snapped out of a trance. "Huh?" She takes notice on the slight annoyed look on the teacher's face. "Oh, sorry. So sorry!" She quickly apologizes. "It's just that… ever since you uh…"

A teen with black mohawk hair with a scuf of yellow shrugs. "Nothing bad. You just have a look we're not used to. You know, pointed ears… the fangs…"

"Bon." A pink haired teen says the name as if to warn him.

Bon simply turns away. "Well, someone had to tell him. Okumura keeps giving us that suspicious look. Keeping him in the dark isn't bright idea." He sticks a thumb at the black haired teen behind him. "Now if it was Rin, it would be normal."

Rin frowns. "I walked in here looking like that. Of course it's normal to you." He crosses his arms behind his head and leans against his chair. "Yukio had been just a Human until recently. Looks like he was wrong when he said he couldn't inherit Satan's powers."

"Rin." Yukio slides his book to the side. "Alright. It's been complicated to grasp. Sometimes I don't understand myself. But, we can't dwell on that. Everyone, please make your ways to your dorms."

There is small hesitation, but the students rise and make their leave. The only one who doesn't budge is Rin.

Yukio gathers his things and tuck them neatly under his arm and walks towards the door. Just as his hand lands on the handle, he turns his head. "Are you planning to spend the night in here?"

Rin jumps from his seat. The entire desk nearly falls over. "You're going straight home, right? I got the perfect meal planned in my head already!" He taps his head with a finger and grins at the last note.

"Unfortunately, I have a meeting to attend." Yukio's reply seems to startle Rin somewhat. He turns the knob and opens the door, but it is shut surprisingly by his brother. "Rin, this is no time for games."

"But, yesterday you said you would come straight to the dorm. I thought you had no paperwork!" Rin seems strongly upset about this change of events.

Yukio opens the door again. "I know, but some things just don't go as planned. I'll see you at dusk. Just make sure you get your homework done." He walks out and the door shuts, leaving Rin to himself.

"Tch. Homework. Is that all he cares about? Damn homework." Rin adjusts his bag on his shoulder and opens the door. His head is hung low somewhat as the door shuts behind him. "I doubt he can even function without a day of work." He makes his way down the hall, appearing drained from the day of school already. "How long until the next break?"

He begins to pass a door but, he doesn't make it through since it swings open suddenly and smacks right on his face. Rin falls on his back with his hands covering his nose.

"Isn't it a marvelous day today? Now that the school day is done, perhaps I can-" The one behind the door peeks out. His eyes shift down and spot the teen on the ground. "Well, hello Rin. Enjoying yourself there?"

Rin blinks and recognizes the voice immediately. He sits up quickly. "Mephisto?!"

Mephisto grins. "I was just stopping by to your classroom to speak with your brother."

"He left for a meeting." Rin says with some frustration. He gets to his feet and sighs. "Why can't he just take a break for once?"

"The both of you are different. It's expected." Mephisto makes his way down the hall. "Perhaps your brother is more concerned with himself. He's been a bit unusual since that day you two saved the world. Perhaps he's not getting use to the fact that he has blue flames as well?"

Rin didn't think of that. "That could be it, but I don't see how paperwork can take his mind off that." He waves as he takes his leave. "I'll see you."

As soon as he steps outside. He takes a deep breathe. He'll take this small moment since he probably won't enjoy it for the rest of the day. He heads for his dorm, but he stops. The atmosphere around him feels slightly different. He could be imaging things, but it is bothering him for some reason.

"All right! Who's there?! Show yourself?!"

He probably looks stupid right now. Screaming at a wall doesn't make him feel any less comfortable.

He shrugs and moves on, but he doesn't lower his guard in case something is a threat. But nothing has happened since that day Satan was defeated. In fact, not one demon has dared to attack him or anyone else. Perhaps because since the gate was destroyed, they have no way of entering the world.

Or maybe, they are afraid.

The thought makes him chuckle. That might just be it.

 **-0000-**

As soon as he arrived home, a small black cat runs at him and jumps to his arms.

" **Rin! You're back!"** The two-tailed feline puts happily.

"Yeah. You must be hungry?" Rin sets his things down and heads for the kitchen with the cat close behind him. "Kuro?"

Kuro nods. " **What about Yukio?"**

Rin frowns at the mentioned name. "He won't be home for a few hours."

" **I thought he said he would be back with you?"**

"That's what I said. It seems that his paperwork is more important for right now."

 **-0000-**

The class is silent as Yukio looks through the pages of his books for a lecture. Rin appears to be half sleep, but when Bon slams his fist on the desk, he snaps wide awake.

"If you fail a test, you're going to complain about it, and it'll be your fault." Bon warns him.

The pink haired teen listens to the lecture a bit more, and he suddenly stands.

"Renzo?" Yukio addresses the pink haired teen.

Shima shakes his head. "I don't know. It's been so peaceful lately… it just doesn't feel right since we're so used to demons attacking 24/7 you know?"

"Well, I guess you have a point there." A younger-looking teen with shaved head and glasses states.

"What makes you say that?" Izumo, the purple-haired girl scoffs. "Miss the action or something?"

Konekomaru, the shaved teen, shrugs. "It's good to have peaceful days like this. We can finally rest, but we can't lower our guard too much."

"Like if a demon would bother us? Yeah, right." Rin leans against his chair, but he leans too far. He flails his arms and the chair tilts back and falls.

"That's what happens when you lower your guard." Shima laughs.

Rin simply huffs and stands up while quickly placing the desk back in place. "Yeah, yeah."

There's a small knock on the door.

"Come in." Yukio's eyes doesn't leave the book he observes.

Stepping inside is a woman who is lightly dressed… well, very lightly. She easily recognized by this, and her tattoos engraved on her chest and stomach.

"What is she doing here?" Izumo sighs with irritation in her tone.

"Well, that's a rude way to say "hello"." The woman chuckles. "But, I can't blame ya. I came here uninvited."

"What is it, Shura?" Yukio asks as his eyes finally shift to her. He shuts his book lightly.

"I came here because of strange activity that's been reported. I figured you would want to know." She says this as if she's teasing him, but Yukio simply brushes it aside.

"I'll keep that in mind."

"Hey." Rin sits up quickly. "What's going on? Don't tell me that demons somehow came around here." He says it as a joke.

"Laid back, aren't you kid?" Shura chuckles. "I wouldn't get too comfortable." She heads for the door and waves with her attention to the exist. "Enjoy your boring lecture. If I stay in here another minute, I might end up sleeping on the job!" She laughs as Yukio frowns at her.

"Some things just never change with her." He shakes his head and opens his book. "Now… Where was I?" He finds the page he was looking for and takes a breath.

The building suddenly shakes, and Yukio is nearly knocked from his feet.

"The hell?!" Rin sits up quickly. "What are they doing?!"

The door opens again and Shura stands at the doorway. "Yeah… this is serious." She walks forward and snatches Yukio by the wrist and leads him outside. "Come on!"

"Hey! Wait a minute!" Renzo springs from his seat and the building shakes again. "Came someone explain what is going on?!"

"Stay in here for the for the time being!" Yukio orders quickly. He looks at his eager brother. "Rin."

"You're kidding!" Rin crosses his arms. There could be an earthquake, but his mind tells him otherwise. He watches the door shut and he turns to the rest of the class.

"What now?"

"It might be an earthquake." Konekomaru suggests, but there's a tone of uncertainty in his voice.

Yukio and Shura stand right outside the door. It had been shut since the discussion is serious and can't disturb the class… At least that it what Yukio hopes is the reason he was dragged out.

"We got a problem. Big." Shura explains to Yukio. "I have no idea how this is possible, but looks like we got demons trying to break into the school."

"What? I thought they can't even enter through here since the gate was destroyed!"

Another voice answers for Shura. "That's what everyone thought, but perhaps they found another way through."

Yukio and Shura turn to the source of the voice. Mephisto casually walks down the hall as if nothing is happening. "They are holding a grudge. Perhaps a powerful demon arrived and broke through the barriers?"

"What?!"

The school rattles again.

"Oh, I think he made it through." Mephisto says as he watches a light bulb fall and shatter on the ground. "Perhaps this is a good time to test out your new abilities again?"

Yukio shakes his head. "I don't want to jump that far just yet." He watches the Demon of Time walk off. "Where are you going?"

"I suggest you get your students out of here before things go out of hand." Mephisto turns and makes his way down another hall.

Shura growls with clenched fists. "I swear, there will be a day I'll punch his-"

"Shura."

She turns to the teen. "What?" She takes notice on the serious look on his face. Her mood settles. "Oh, right. I think I know who this is. He's probably the only one who could do this without a problem."

Yukio is shocked to hear this. "Wait… you know?!"

"I recognize that demon anywhere. He's a huge threat! We never faced anything like this one!" Shura sounds frustrated about this. "If only he showed his face sooner, then maybe he wouldn't be such a problem!"

"And he's in the school?!" Yukio glances around quickly. "He easily broke through the barriers! This demon must be in an entirely different level!" He waddles as the floor shakes. "I need to hurry and get back!"

Shura extends her and at him as hs runs for his classroom. "Wait a minute! Don't run off just yet! That demon has brought more than we think it did!"

"What did you say?!"

Suddenly, the walls break down as a swarm of small demons fly through and enter the school halls.

Yukio has to slam his feet on the ground to stop his sprinting. Several goblins run through the halls. "I don't understand! What is going on here?!"

"He's brought a huge burden! That's for sure!" Shura reaches for her chest and says a small chant to pull her weapon out. Drawing a drop of blood from her fingertip, she smears it across the blade. "Snake Fang!" With a powerful swing, an air blade slashes through the goblins and kills them off. Just as they die, more pour in. "Damn. Looks like we have to play exterminator for a while."

Yukio draws out a pair of guns from under his jacket, and he fires them rapidly at the low-level demons. He takes them down with skill and great accuracy, but it seems never-ending as more swarms pour in. He pulls the triggers and only one gun fires. He swiftly unclips one case and thrusts the gun down towards his belt, clipping on a fresh new round and fires once more.

Another swarm flies in from the opposite end of the hall. He throws a hand to that direction and now he fires at both ends of the hall. Shura is busy slashing her way through.

The swarms seem to thicken, and Yukio has one gun knocked aside. Just as he spins around to retrieve it, goblins slam on to him in groups and he is knocked down. He drops his other gun as he throws a few of the goblins off him, only for more to jump on him.

Shura swats the goblins in her way aside as she rushes over to the exorcist. "Yukio! Are you alright?! Get up, will ya?!" She slashes the goblins surrounding Yukio, and prepares to take down the ones covering him in a pile. "Is it me, or are these things harder to deal with than usual?"

A demon lunges from behind her and attempts to chomp her down. She stabs through it's chest and throws it aside. "Hellhounds? Why send the low-level demons after us?"

"I… wish I know the answer to that!" Yukio snatches the gun near him from the ground and fires at the goblins on top of him. The weapon slips from his hand as he is yanked back. It falls under him, and he is forced to the ground.

"They are very stubborn! What are they trying to do?!" Shura rushes towards the goblins and kills them off quickly. She glares at the demons piling on top of Yukio. "Hey!"

He can't breathe. Not like this. They still pile on top of him. His gun is crushed underneath him. He can't reach for it. ' _Where is Rin?! He normally would barge around by now!'_ It's not that he relies on him much, but it's unusual that his twin brother hasn't shown just yet even after he was told to stay put. His thoughts are interrupted as the air is crushed out of him. He screams from sudden surprise as his foot is chomped on and pulled back. He can't move at all now, and he's growing frustrated.

He growls under his breath as he tries to push himself up. He is shoved back down, and his last straw had been pulled.

"Damn it. They just don't quit!" Shura impales another hellhound and runs towards the demon pile. Just as she swings her sword back to prepare to slash them off, blue flames explode and ignite the demons in a huge burst. She is forced to jump back. "The hell?!" She watches the goblins who are lucky not not get scorched flee from the flames. She looks back at where the pile use to be, and Yukio is on his knees, breathing heavily.

Yukio's ears have grown sharp and long, and his fangs have grown in length. Blue flames are lit in many places, shrinking until they are small.

"He can do that too…?" This might be hard to take in. Rin is able to summon his power without the sword at times, but he never saw Yukio do it. Then again, he did seemed to be in stress. "Damn it, Yukio! Calm yourself down! We don't want anyone seeing you like this!" If it was his class, that might be a small awkward issue… but if anyone else saw, that might be a huge problem. Most already know of Rin's abilities, but Yukio's a whole other story.

Yukio stares at the palms of his hands which hold small blue embers. He balls them into fists and takes a deep breath. This never happened before. He lost his cool for a split second, and he changed appearance suddenly. "I'm going to have to be more careful…"

For a moment, he is on his hands and knees. He picks up the sound of footsteps. He slowly turns his head and sees his twin brother running alongside Shiemi and Bon. They heard the commotion and must had decided to investigate.

"Everything okay over here? I thought I heard shouting…" Rin's voice trails off. He blinks at his brother. "Yukio?"

"What the hell?" Bon tries to wrap his mind around what he sees. "What happened? Why are you…?"

"To be honest, I don't know myself. I was overwhelmed I guess, and the power just came out." Yukio stands and sighs. His body manages to revert to his usual appearance. He takes his gun that Rin picks up for him. "Thanks."

"Do you know what's going on?" Bon asks.

"That, I wish I know." Yukio frowns. "For some odd reason, the demons that are usually easy to take care off are harder to hit, and they have small bursts of sudden strength. Where this is coming from… I don't know."

The school shakes violently once more. Dust from the ceiling rains down.

"Looks like we might get answers." Bon mutters.

The walls from the left side rip apart. A giant hand snatches Rin by the leg and yanks him out the building. The teen yells in surprise.

"Rin!" Yukio didn't see that coming. The others didn't either, but he won't stand around. He grabs his firearms and makes a dash through the hole that leads outside. He fires his guns and the bullets don't seem to hurt the giant creature. His feet slam from concrete to grass as he enters a field further from the cram school.

"What is going on?" Shura hears footsteps and turns around. The rest of the class has arrived.

Izumo is the first to speak up. "Can someone explain what is going on?!"

Shura shrugs. "We are just as confused as you are. However, I have a feeling whoever is behind all this is why these small demons are harder to take down. They are after Rin." She steps through the new doorway. "I'm going after it. What you guys do is your decision to make."

As she leaves, Shiemi seems to be worried with thought.

Bon steps forward. "I'm going after it. Whatever it could be, it's going to pay for what it did to this school!" He runs after Shura, and the rest of the class follow.

Just as they arrive at a field, they stop all together at the sight of a 10 foot beast holding Rin by the ankle upside down. It has the appearance of a humanoid goat when it comes to the body. The head is basically a monsterized goat beast.

"Wh-what is that?!" Konekomaru yelps in surprise.

Shura and Yukio stare at the beast in shock. Never have they seen anything like it before.

"Just great. There's always something!" Shura frowns. "They might as well send in everything at this rate!"

"I don't like this." Yukio studies the demon standing before them. "I've seen pictures of that demon before. Some say it resembles Satan… but this thing here… I would say it's the the closest you could get… "

The demon notices the presence of the exwires and exorcist. He turns and faces them all. "The True Cross Academy. These are the students and teachers standing before me?"

"Who are you?!" Yukio demands for answers. "What do you want with him?!"

"I came here to bring forth vengeance. This boy's victory was a mere fluke!" The goat's eyes narrow. "It seems that he certainly wasn't alone. From your appearance, you are his brother. So, it's true when they say you might just have such power? Don't lie, I can see your ears and fangs from where I stand."

Vines explode from the ground and wrap around the demon's feet. He is pulled back and his arm is yanked back as well. He is forced to free Rin to tear the vines off him.

"Good job, Nee!" Shiemi praises the Greenman who happily squeals the word it was addressed by.

The demon growls and rips free from the rest of the vines. "Stay out of the business!" He raises his arm, and bullets bounce off of it. He glares at the twin responsible.

"Don't you try to hurt them!" Yukio shouts at the beast.

"Time to get this show on the road!" Rin pulls his draws his Kouma Sword, and blue flames engulf him quickly as his ears and fangs stretch and are pointed more. His tail whips behind him as he rushes forward.

Yukio expected the weapon to draw out his power as well, but nothing happened with him. He isn't bothered by it. He simply continues with his firing and changing rounds when needed. "Hey! I need everyone to put effort into this! Don't get too caught up, but taking this demon alone is dangerous!"

Shura frowns. "Don't get too focused with this demon. The other ones are still out there! Keep your guard in place!"

"Right! I-I hear you!" Renzo replies. He turns to his friends. "Hey, Bon?"

"Yeah. I'm on it!" Bon nods.

"Hah!" The demon swats Rin and Yukio aside. His tail beats on the ground as the fraternal twins stand. "Go ahead and try all you want. As long as I'm here, I have influence over every demon you see!"

Rin sprints forward with a swing of his sword, the beast steps back but is still grazed. He dives down as his brother begins rapid fire. The bullets batter all over the demon who grows more irritated with every hit he takes.

"Anything yet?!" Yukio calls back to his students.

"We're still trying to find the right verse!" Konekomaru announces over the words Bon is reciting. "I don't know if any would work against something like this!"

"Just keep trying!" Yukio ducks in time to avoid a row of claws that attempt to scratch him. He fires his guns and more bullets sting the demon.

The goat demon growls and steps forward. "You're getting on my nerves!" His tail whips out and a smacks Yukio from the ground. The exorcist rolls across the field before lying still.

Rin stares at his fallen brother for a second before glaring at the demon. "That does it! You're dead!" He rushes forward and dodges the demon's attacks before lunging at him. His attack is easily dodged, and the demon punches him down. Rin falls and lifts his head up, only for a foot to stomp on his stomach. His scream is mixed with a painful gasp as a mouthful of saliva flies from his mouth. His weapon clatters on the ground. Small embers are still ablaze. Rin reaches for it, but the demon kicks it back with his other foot, and it slides back into the case, forcing Rin to revert back to normal form.

"That was only entertaining for a moment. It all ends so soon it seems." The demon kicks Rin like a ball. "It's not a good feeling to be easily overpowered!"

The others can't do much but watch and hope that this would end somehow. A mericial would be nice, but from the way things are looking, even _that_ might not be much help anyway. They hope that Bon would come across the right verse to at least wound this demon.

Konekomaru and Shima refuses to watch the Okumura brothers suffering much longer. They run for the beast, demanding for the violence to stop.

Yukio fears for them. He had made the mistake of asking for some assistance. The demon is far too dangerous. He tries to warn them. "No! Stay away from him! He'll kill you!"

"We won't stay back again! We can't lose you!" Konekomaru protests.

The demon huffs through his nose. "Stay out the way!" He swings his arm and knock the pair aside. He extends his arm to reach for Konekomaru, but bullets batter all over his arm. He draws his arm back and glares at Yukio who constantly fires his guns.

"I wouldn't go too far if I were you." The demon warns him as he rises his foot. "I will crush your brother until he's nothing more than a bloody pulp!"

Rin struggles underneath him. "Whoever said I would give up against you so easily?" Hs takes the opportunity and scatters from under the foot. He dives at the ground as the demon attempts to hit him. As he slides, he reaches for the Kouma Sword.

A heavy tail smacks it aside, and now it's too far to reach. Rin rolls to the side to avoid being stomped on. "Alright big guy. You asked for it!" He charges forward and dodges most of the sent punches. His feet leave the ground as he jumps and his hands grasp around the pair of horns on the demon's head. The demon tries to throw him off, but he hangs on. "This is your chance, everyone!"

Izumo is one of the first to react. Taking out the pair of small drawn circles on squares of paper, she begins to say her usual chant. The word "humbly" doesn't come out her mouth as a sudden force blows her off her feet and tear the pair of papers to shreds.

"This guy… is too much for us!" Konekomaru gulps.

The demon snarls and throws his head back. Rin is catapulted off of him and spirals to the ground.

Renzo is quick to react by picking up the Kurikara from the ground. He rushes towards Rin and gives the weapon a good toss. "Okumura!"

"Shima?" Rin quickly turns and sees the weapon propelling towards him. He catches it just as the beast turns to him. He prepares to draw the weapon out, and the demon lashes for him, delaying the action. He jumps up and runs. Claws stab through his back, and he falls face first. Hs quickly rolls and his left side is stabbed through. He screams in pain.

Yukio sprints towards the demon. "Rin!" He aims the pair of guns at the demon's head. A pair of goblins dive from nowhere and snatch the weapons from his hands. "What the?!"

"You can't be serious!" Shura scolds him as she reaches his side. "I told you to not lower your guard by being so focused with this demon! The others are still around!"

Izumo reaches him quickly with a round of bullets in her hands. "This is all I could retrieve." As the bullets are taken from her hand, she shakes her head. "Get your head out the clouds! There has to be some other way!"

It's unlike him to forget about the other small issues. It's understanding. His brother is in a situation that needs to be prevented from going on any further. "Release him!" He throws his demand at the demon, but all it does is make him laugh.

"You expect me to just let him go? You must be blind to the fact that I am here to avenge my master by slaughtering you both!"

Yukio's fingers curl as they appear to be trying to form fists. His teeth are clenched as he tries to think of a way to pass this situation and help his wounded brother out. Though Rin's wounds will heal quickly, it's only a matter of time until the demon wounds him too far. Seeing the demon slash at his brother again hurts him. "Stop THIS!"

Izumo and Shura step back startled seeing sudden small flames burst around Yukio when he screamed the demand.

The demon's eyes shift and observes Yukio. "What's this? The blue flames… you have them too? Interesting." A second passes and he roars with laughter. "What are you going to do with those?! Make a barbecue?!"

The flames disappear and Yukio steps back. He glances at his hands for a second before looking back at the demon. ' _He doesn't know that the power has grown. It's not a good sign if these flames come out without the sword drawn. This is the second time it happened.'_ He takes a breath to calm down. "I'm giving you a warning. Release him and leave!"

"I don't take orders from the likes of you!" The demon replies rudely. "However, perhaps I can toy with a little?" He drops Rin to the ground and slowly walks towards Yukio.

"What are you doing standing there for?!" Shura yells at him. "Get out of there!"

"Just do me a favor and make sure the demons don't do anything to the school and further. Keep my students out of this!"

"You must be out of your mind!"

"Just listen for once!" Yukio snaps for a second. The tone in his voice makes few of his students shut their mouths to keep their own arguments sealed.

Shura would argue further, but changing Yukio's mind is almost impossible once he sticks to a decision. "Getting through to you is just as hard with Rin." She grabs Izumo's arm to force her back while she pushes the rest of the class back. "You heard the man. Stay back unless you're needed."

"Is he serious about this?!" Bon hates this all together. "Why is he just standing there?!"

Yukio stays firm in his place. His hand rises and tugs on his jacket. "None of us are through just yet! You've made a mistake coming here!"

The demon roars and charges for him. He nearly falls as his ankle is snatched and pulled back by the older twin. He kicks his leg back and throws Rin off him and punches him midair.

"Rin!"

Perhaps he made a mistake.

* * *

 **A/N:** **Finally finish!**

 **Huh. Not too bad for a first Blue Exorcist fic.**

 **Well, I did my best to stay in character… but I felt I slipped now and then. Still, this is okay. I made sure I had all the information right.**

 **The goat demon is a known demon. Google it. :P**

 **Well, the second part of this is coming soon. This is a three-part fic!**

* * *

 **REVIEW! REVIEW!**

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 **To be continued to Part 2!**


	2. Part 2: Don't Panic

**A/N:** **Espeon804 here with another… well, I wouldn't call it a chapter…ehhh…**

 **These a basically like a one-shot… I don't know what to call it.. A novelette? Is that what they call it?**

 **Eh.**

Key:

"Talking"

 _'Thinking'_

 **"Telepathy"**

 **DISCLAIMER:** **I DO NOT OWN Blue Exorcist! Kazue Kato does!**

 **I wonder if he was involved with the anime branching off from the manga... or was that the animators? I don't care anyway, the last 3 episodes were epic!**

* * *

 **Check out my most popular fanfics! "Of The Earthling Saiyan" series! Both, "The Wrath" and "The Retaliation"!**

 **-Espeon804**

* * *

 **\- Part 2: Don't panic -**

"RIN!" His brother's name bursts out of his mouth as he witnesses him crashing on the ground. "RIN! GET UP!"

Renzo swings his staff and knocks one of the goblins down. A gun falls with it. "Here!" He tosses the weapon at Yukio who catches it quickly.

The demon slowly turns to the younger twin. He grins and laughs at the shaking gun aimed for his head. "What are you going to do? You're nothing like your brother. You have always been so behind." He charges forward and throws a punch that makes contact on the exorcist's stomach. The gun flies from his hand as he falls. He coughs out blood.

"Okumura!" Bon says alarmed. "Dammit! What the hell is happening?!"

"Yuki!" Shiemi claps her hands together, feeling helpless on what to do.

Rin digs his fingers into the dirt as he slowly lifts his head. "Y-Yukio…" He extends his hand in hopes to reach him, but his twin brother is too far.

Yukio drops to one knee and fights to control his coughing. The demon crushes the gun under his foot before the twin could consider on reaching for it. Now he stands over him, but Yukio has prepared for this. "That's… enough!" He quickly draws out a separate gun hidden under his jacket and pulls the trigger. With a powerful boom, the demon is struck and screams in pain. He sees the opportunity. Yukio clumsily stands. "Quickly, everyone! Back to the building until this is over!"

Izumo isn't happy to hear the orders she was given. "What?! Are you crazy?! Fighting that thing alone is reckless! You'll get yourself killed!"

"I would rather die by that thing than to witness my students being mauled with me being helpless!" Yukio proves his point. "Hurry! Get out of here!"

Shura shrugs. "He has officially lost his mind."

"What about Rin?!" Renzo calls out. "We can't just leave him!"

"I'll deal with that. It's my sole duty to protect him after all!" Yukio jumps back and pulls the trigger again. "Run!"

"No way! We are not running! Not again!" Bon steps forward. "It's either you or Rin throwing us aside! I'm sick of standing in the sidelines! We're fighting too!"

The exorcist had expected this to happen. Bon has always been stubborn about not joining the fight. "You have to listen to me! This is not a demon we have faced before!" Yukio reminds Bon, but it's more towards himself as well. He never faced a demon like this. It's why he can't endanger the others.

"I don't care!" Bon marches forward with Konekomaru and Renzo behind him. "We are all fighting, whether you like it, or not! Stop trying to-"

Yukio swings his left arm, sending blue flames spewing near Bon's feet. The teen and the two behind him are forced to stop. The other students stare at him in shock, but he isn't fazed by this. "Stay back!" His voice sounded somewhat dark. His body is lightly lit. "I'm trying to-" His words are cut off as he is shoved to the ground by the demon. He quickly jumps back to his feet and prepares to fire at him again, but he is startled as the weapon is knocked out his hand. "What?!"

Really, the guns leaving his hand for the third time has grown very annoying now.

"I say… that's enough!" The demon swats Yukio from the ground and chuckles at the sight of him crashing into a tree.

"Damn it… that bastard!" Rin snarls under his breathe as he fights to at least get on his knees. "I thought we could get a break after defeating Satan! These guys just don't know when to stop!" He props one knee up and picks up his sword from the ground. His brother had been knocked far, but closer to him. "I… I wish I can stand… but right now.. Yukio…!" He screams his name. "YUKIO!"

Yukio blinks away the blurriness in his eyes and gets to his knees. Just as his vision is clear again, he notices his brother looking at him. "What is it?!"

"I can't shake the feeling, brother." A green hamster with red eyes climb on Mephisto's shoulder. It blinks at the scene, taking a seat on top. "You knew that Yukio had potential all along?"

"These two brothers have a lot in common… more than they think." Mephisto explains, watching from the rooftop. "Yukio's flames have been lit and summoned power he never felt for months. He never felt such a powerful rush."

The demon growls and charges towards the two brothers.

Rin gulps and gives the sword a hard throw. "Here! Catch it!"

"Wh-what?! Why are you giving this to me?! I don't fight with swords!" Yukio catches it anyway and glances at his brother and the demon.

"You have nothing else to defend yourself with! Use what you have!" Rin screams at him.

"H-he's right…" Yukio stares at the shielded sword in his hands. "But… how can I be so sure?"

"Okumura!" Bon yells at him. "Damn it! Look out!"

Those words snap him from thought. Yukio sees the demon throwing down his fist. He grabs the handle of the sword and its scabbard, and he twists the two apart. Blue flames leak from the edges.

"Say goodnight!" The demon roars with laughter.

Before his fist could strike him, he is greeted by spewing blue flames that blow him away. "Wh-what is this?!"

"Ooh… I don't think I'll ever get use to seeing this." Renzo groans at the appearance of his teacher.

"Hopefully, he'll end this instead of playing around like Rin would usually do." Shura ignores the glare Rin gives her.

Yukio stands with the sword drawn out and blue flames surrounding him. His ears have grown and stick out more pointed, and his fangs have grown in length. The flames surrounding him appear more bright than before. He narrows his eyes. "Leave them alone! You should be focused with me!"

There is a pause, and the demon begins to laugh. "What is this?! A light show?! Those flames are small compared to your brother's!"

"I don't care." Yukio growls. "This is your last chance to leave! Take it, or you'll regret coming here!"

The goat demon begins to laugh. "You expect me to be afraid… of _you_? Look at you! You have always been so weak and frail! What makes you think you're any match against me?!" He reaches down and his hand clamps around the exorcist's throat.

"Yukio!" Shima panics at the sight of the teacher being slammed on the ground.

Now, a pair of hands clamp around his throat. Yukio tries to pull them free from choking him, but it proves to be almost impossible.

"You have proven to be more difficult to pin down more than I thought… but now, I have you where I want you!" The demon laughs at the terrified look on the twin's face.

"Leave him aloooone!"

"What?!"

Rin throws his arms around the demon's head. "Hurry! Get out of there while I still have- AAH!" His body is thrown against a building, and he slides down and falls to the ground.

"Rin!" Yukio extends an arm, and his words are cut off again as more pressure is applied.

"I say we end this now. Don't you want to see your poor old daddy again?" The demon laughs at the shocked look he is getting. "Not much has changed since he died I guess. He might burn in blue flames again. Your friends can join you. It'll be a nice reunion!"

Yukio thrashes as more pressure is added. Anymore, and his neck might snap.

"Poor young Humans. Die young and never will they experience the world!" The demon grins. "Perhaps I should start with the shy one?"

Shiemi shrikes and shrinks as the demon drags Yukio and walks towards her.

"He's pushing him. Not very wise." Mephisto observes with a content expression. "Yukio's flames are starting to grow wild." He glances at the hamster standing on his shoulder. "I say that our little brother here has a lot to learn just as our other does? Is that what you believe, Amaimon?"

"Not as much as Rin, but he still has much." Amaimon replies. "Looks like he's in panic. He'll eventually slip. Then the fun begins."

"No…!" Yukio manages to choke out. "Don't… hurt them!"

"Oh, don't fret. They won't feel a thing!" The enemy laughs. As he draws back his hand. "They'll just be a bloody pulp in seconds!" He swings down his arm at the screaming girl.

Yukio's eyes widen with sudden anger. "Leave them ALONE!" He snarls as he thrusts his hand at the beast. The blue flames bursts and strikes the demon off his feet.

"What the?!" The demon stands and stares at the Satan spawn who did this to him. He blinks in surprise at the sight of the blue flames spewing bigger than before. "This isn't right! He shouldn't be able to do that!"

Yukio stumbles as soon as he is on his feet. He gets a firm placing on the ground, and his hand tightens around the handle of the sword. "Who do you think you are… to come here and ambush us like that…?!" His burning eyes glare at the demon. "Well?! What do you want with us, or are you after me and my brother?!"

"You think you are so tough." The enemy steps forward and Yukio tightens his hold. "You're trying to look tough, but in the inside, you're quivering in fear. You've never been in a situation like your brother has… not like this." He steps forward. "Not with a sword." He steps forward again. "And definitely not in this form."

"Wrong!" Rin stands from afar, leaning against a rock for support. "We both took down Satan! You're nothing compared to him!"

The goat beast laughs. "I'll have you know that I worked with Satan for centuries and thousands of years! You're facing one of Gehenna's most powerful demons! A demon so powerful, the both of you are like kittens!"

"You must be bluffing!" Rin snarls. "I'm not buying any of that crap!"

"Aren't you already wounded enough? Then again, you have healed quickly already, which explains why you are still standing. Stubborn idiot!" He charges forward and throws his head back. "Overconfident brat!" He throws his head down and shoves it forward.

Rin quickly ducks and avoided the pair of horns that nearly impaled him. He picks up the sound of air movement and turns to his right. He screams as his right side is slashed by sharp claws that easily tear through his clothing and draw blood. He crashes on the ground. The flames surrounding him shrink and begin to turn dim.

"RIN!" His classmates scream in horror. The beast walks towards the teen and picks him up from the ground.

"Let him go!" Yukio stabs the sword through the demon's back. The goat hollers and throws Rin aside and swats at Yukio. He is struck down and falls on the ground.

"Persistent pest!" The demon roars in fury. His tail whips out and knocks Yukio flying into a tree. He turns to Rin. "I'll rid you first since you're the main issue!" He reaches for the teen and picks him up. His free hand reaches for Rin's head.

Yukio shakes his head and rubs away the throbbing pain. His eyes blink and they meet a scary scene. Through the cracks in his glasses, he watches the demon preparing to tear off his brother's head. His eyes widen in terror. "S-STOOOP!" He has once again caught the beast's attention. He stands again but hunches over slightly.

"You don't know when to stop either? If you had played dead, I might had considered on killing you last!" He tears a tree free from the ground and throws it at the twin. "Wait for your turn!"

Yukio shuts his eyes as his arms cross over his face. He thinks that he might just die.

But Rin…

And everyone else…

They will die too… probably in worse ways than _him_.

His blue eyes snap open. "I won't let you do this! I WON'T!" At the last two words, the blue flames busts and grow twice their normal size for a brief second. The tree is engulfed by the flames and turns to ash in mere seconds. He drops his arms with his mouth agape. Next, he shuts his eyes with his hands gripping on the Kurikara. He takes a deep breath in hopes to calm himself down, but he simply becomes more frustrated. His fear is being replaced with anger.

"Whoa!" Renzo gulps, watching with his classmates from afar. "Hey, Shura… please don't tell me Mr. Okumura has lost his mind!"

"Maybe he did." Shura sighs. "Looks like we have another problem in our hands. We can't let this be known."

The demon narrows his eyes. "His power just grew." He turns to face the teen. "He's afraid." His hand rests on Rin's head. "Terrified, aren't we?" He begins to pull, and Rin begins to scream.

That's it.

Yukio screams and charges forward. He springs from the ground and swings the sword down. It stabs through the beast's hand that holds Rin.

"AAARGH! Why you little…!" The beast drops Rin and swings an arm at Yukio and misses. The sword slashes his arm, and he steps back as the flames cover the new wound from the impact. "I'm growing tired of this!"

"Go back to where you came from!" Yukio swings the weapon again and it slashes the demon's back. He kicks the enemy, and the demon skids across the ground. As his feet touch the ground, Yukio fights to catch his breath. He can feel his anger growing, and he can't tame it. Every time he wounds the demon, it makes him feel so much more powerful… almost as if he's invincible. These feelings of power mixed with anger, he knows it's a bad sign, but his mind is too clouded for him to figure it out. He feels himself slipping into something… and he doesn't want whatever it is.

He hears heavy stomping, and his mind leaves the subject as he looks up. The demon is ready for another round. He's more aggravated that it won't just lie dead. A part of him is scared, because he _wants_ it to suffer and die. He knows what it could be, but he can't find the reason behind it.

Renzo speaks with his voice slightly shaking. "H-hey… Okumura? Is everything okay with you?"

As the demon comes close, the exorcist can feel the heat from his flames becoming warmer.

The goat beast runs forward and punches Yukio on the head. The teen falls on the ground and slides across the field with a trail of blue flames being left behind as evidence. The trees caught in the trail are engulfed with the flames. A few would fall and spread the fire.

Konekomaru gulps and speaks nervously. "You know… for some reason, this feels very familiar!"

Izumo realizes what could be happening. "Yukio… he must be scared or something! Don't tell me he's gone crazy?!"

The demon walks heavily towards the teen. "You're becoming a bigger burden than I originally thought!"

Yukio's eyes go wide as the demon's claws grow. The demon plans to kill him… then he'll be after everyone else.

A final wave of anger with that thought. He'll kill it.

He'll kill it before it kills _them_.

The beast throws down his hand, and the flames bursts. His hand is caught in the fire, so he draws back quickly the second he sees his hand as a torch. "What is this?!" He steps back and his left leg is slashed by the sword. This happens again with his other leg. He takes more steps back and the third swing misses. "It's enormous… almost exactly like his brother's! Just like… Satan!"

Bon doesn't like this. "What did he just say?!" He turns his attention to his teacher. "Okumura!"

Yukio lifts his head and stares the demon down. He jumps forward with a shout and throws the sword down. It collides with the demon's horns. He struggles to shove him down.

"Oh, look. He's really angry now. See how frustrated he is?" The hamster points out. "He can't take the demon down, and that really bothers him."

Yukio's teeth are bared as he finally shoves the demon down. Watching him fall wasn't enough. He slashes him across his chest, and the burst of flames blow the demon back several yards.

"He's becoming merciless." Shura takes note of what she sees. "In fact, he's becoming very aggressive. I don't like this. Don't tell me that my thoughts of this was right."

Yukio's feet touch the ground as the beast crashes. He sprints towards him with a long growl.

"Oh, dear. It's like a flashback." Mephisto sighs as he takes a sip of a drink from a teacup.

"This is ironic." Amaimon says. "The teacher has forgotten the most important thing about himself. So, now he doesn't have control of his flames anymore… Right, big brother?"

"Yukio… the calm and collected exorcist… is now feeling the desire for destruction like a true demon. Just like Rin had when he fought you in the forest." Mephisto explains. He watches the blue flames spewing every now and then. "He's overwhelming that demon by fighting him so quickly now… but it won't tame him just yet."

Rin waddles to his feet in time to see blue light shining from behind him. He turns around and sees the flames bursting in huge clouds from where his brother is. "This is bad…! Yukio and I only won because we took Satan down together. I was sure he had full control like I did, but he must be in panic or something… unless he's lost all composure!" Another busts of flames answer him. "Shit! Yukio has lost it!" He flinches as pain explodes all over him. He can't run, but he refuses to stand back. "I need to get to him before he ends up hurting someone!"

"That's it! You're afraid of them losing their lives to me!" The demon swats at the teen who dodges. "And because you are afraid, you powers have slipped from your control!"

Yukio opens his mouth wide and he screams in fury. The flames surrounding him grow huge like a giant torch. He swings the sword in a flash, and the demon screams as his struck arm becomes a flaring torch as well and begins to break apart. With a hard thrust, the sword stabs through his chest, and the demon stands and gasps. It snarls in anger and disbelief. "NOOO!" The demon roars. "This… can't be! I shouldn't be defeated! I CAN'T!"

Shiemi covers her mouth with a gasp. Next, she covers her face, not wanting to see anymore of it.

Yukio's burning eyes shift to observe the demon. It appears to be suffering. It'll die in a minute… or two… but he's growing impatient. He has decided.

He'll finish it.

He yanks the sword out and leaps into the air and swings the weapon down once more. It cuts right through the beast, starting from the top of his head…. slicing him in half.

The goat beast howls as his entire body is engulfed and begins to break down until mere blue embers rain down. Yukio lands and stumbles heavily, whiping his head back wildly while growling. He lowers his head, and his blue and red eyes stare at the horrified class.

The students stare at the spot the beast previously stood. They slowly turn to their teacher who is panting heavily and looks as if he's about to pass out. Behind him, trees and bushes are ablaze. The blue light illuminating on him makes him appear more intimidating than he already is.

"Splendid! This is the true power of Yukio Okumura! His potential as a demon is great indeed!" The demon King of Time throws his arms in the air in praise. "I never thought that he would slip from control of his flames after perfecting it with his brother, but not all things are what they seem. Sometimes, even the experienced can make mistakes."

"And what was his mistake, big brother?" Amaimon is curious.

"He lost his composure, and the flames took control of him. Anyone can realize this by now. He had the demon defeated when he caught it's heart with the Kouma Sword, but instead of stepping back and letting death take it's place in a minute, he finished it off." Mephisto explains as he crosses his arms.

Rin arrives by sprinting into the scene. He skids to a stop at the sight of his brother. "This is really bad…"

The exorcist takes heavy steps back to prevent himself from falling. His wild eyes seem to be ablaze as he throws his head back with a feral scream. The flames engulfing him grow bigger and wilder, and the goblins who were unlucky are caught in the flames and are turned to ash. The rest of the goblins realize what happened, so they flee. All that the students can do is watch.

"Damn it! He just had to lose his grip!" Shura screams at him now. "Yukio! Snap out of it!" She growls. "This is not like him to let this happen."

"Yukio… why did you allow the flames to consume you…?" Rin mutters.

This had never happened before. The first time Yukio had his demonic power summoned, he was possessed by Satan not long after. When he was free and fought, he had full control… he did and his brother. They both took down Satan together with their power.

Then again… Yukio just had his power summoned. He never really knew how it felt to have the flames beyond their limitations.

Yukio is afraid.

Afraid and enraged.

"You… must be terrified in there… to not know what's going on…" Rin steps closer, and his brother growls at him. "Looks like we swapped roles here. This time… I'm the one trying to calm you down huh?"

"Something tells me talking to him won't be enough to calm him down!" Konekomaru calls out.

"Yuki…" Shiemi shakes her head, and she sprints forward. "Yukiooo!"

Rin turns around. "Shiemi! Stay away from him! He's dangerous right now!"

His pleas are ignored, and Yukio turns his attention to the girl running towards him. He swings out his arm, and a trail of flames blast right towards her.

Shiemi halts and screams. Her arms shield her face.

"Oh, no! He's attacking Moriyama!" Renzo prepares to run for her, but Izumo pulls her back. "Hey!"

"Are you trying to kill yourself?!" Izumo scolds him as she fights to pull him back.

"Are you trying to let her die?!"

"Shima! Don't be an idiot!" Bon growls. "We already know it won't happen!" His attention turns to Rin.

Rin jumps in front of Shiemi and crosses his arms over his face. The flames slam right on him.

"He couldn't just _push_ her out the way?!" Bon shouts with shock and anger on the stunt Rin just pulled.

Smoke rises from his scorched arms. Rin lowers them slowly to his sides. "So… it seems that bringing you back won't be so easy." His eyes shift to his brother's as his own body is ignited. He reverted to his demon form.

"Oh. This just got really interesting!" Amaimon is entertained with what he sees. "The two brothers are about to play!"

"Don't try to be involved." Mephisto warns the hamster. "This is a situation that must be handled by Rin. Makes me wonder… how will he calm his brother down?" Now he's really interested. He watches the scenario as if it's a 5-star rated movie.

"You're not serious, are you?!" Bon finds Rin insane at this point. "Fighting him won't solve it, dumbass! You'll make it worse!"

"I agree with the kid." Shura sticks a thumb at Bon. "Do you ever use your head, Rin?! Yukio is acting just as you did when you fought Amaimon back during the camping trip!"

"Well, this is my brother we're talking about." Rin frowns without turning away his attention from Yukio. "I'm not allowing him to hurt anyone! He'll be in pain to learn that he killed somewhat like this!"

Shura sighs and steps forward. "Well then, I'll just deal with this-"

"No." Rin turns down her assistance immediately. "If he had to face more than one, bringing his senses back is almost impossible. Let me take him on. After all, he's suffering in there, and I will bring him out. Just make sure he doesn't hurt anyone."

"You're just as crazy as Shiro." Shura frowns.

Yukio's hand holding the sword seems to shake with the growing rage. His lips part open, showing a portion the pointed teeth and fangs. As Rin steps closer, the teeth are fully exposed with a snarl.

"Hand it over. You defeated that demon. There's no reason to be angry anymore." Rin speaks to him carefully.

Instead of cooperating, Yukio's feet leave the ground as he lunges forward with a feral shout. Rin narrows his eyes as his hands form into fists.

"So be it. I'm left with no choice."

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 **A/N:** **Finally finish! Whew! Two down, one more to go! Since these are not what I would call chapters, they aren't so long. On average, my chapters range from 13,00 to 18,000 words. (I'm trying to bring it down to 15,000. My most recent chapter on "The Retaliation of The Earthling Saiyan" had... 19,000. O.o**

 **Yeah. But, many said it was a really good one, so I don't feel so guilty. This is around 5,000 words! XD**

 **Like I said before, this might not be great since this is my first Blue Exorcist fanfic.**

 **And, it's based off the English dub of the anime. (As I said before) so if you are familiar with the original version, it's understanding. You might be confused. :P**

 **I actually have that episode "An act of kindness" as one of my favorites. It was for the small humor, and the fact that we get to see not only Rin expose his power to his classmates, but he went berserk while fighting Amaimon.**

 **I know the Kurikara broke somewhat. But that alone wasn't why Rin went crazy. It broke while he was fighting with rage. His flames consumed him already before that.**

 **So, this part is really good in my opinion, but I felt it's a bit sloppy in some parts. I dunno.**

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 **So... part 3 will close this story.**

 **HOWEVER, I will gladly make this a chapter series if you wish. I actually enjoy typing this. It will be extended if a lot of you wish for it to be that way.**

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 **REVIEW! REVIEW!**

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 **To be continued to Part 3!**


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